Handheld or portable debris vacuums are commonly used by homeowners and professionals alike for the purpose of removing debris from yards, driveways, sidewalks, etc. These devices are sometimes configured as convertible blower/vacuums (“blower/vac”). A convertible blower/vac is a portable device which can be configured for use as either a debris vacuum or a debris blower. When used in the blower configuration, blower/vacs provide a sweeping action created by the production of a fast moving stream of air generated by a rotating impeller located within a housing of the blower/vac. When used as a debris vacuum, replacement of various blower components on the housing with vacuum attachments allows leaves or other debris to be vacuumed into an attached debris container.
In either configuration, the impeller draws air into the housing through an air inlet and exhausts it through an air outlet. With a debris vacuum, air and entrained debris may be pulled into the unit via the air inlet and expelled via the air outlet into the attached debris container. The operator may then use the comminuted debris as mulch for gardens, flower beds, etc. As one can appreciate, the ability to comminute or shred this debris is advantageous as it permits more dense packing of the debris within the debris container. As a result, the container requires emptying less frequently, potentially allowing the operator to finish vacuuming more quickly.
In many conventional debris vacuums, the impeller assists in the comminution of the vacuumed debris. However, the impeller is typically configured to maximize air flow, e.g., to improve operation as a blower. Although such designs have proven effective for mulching debris, impellers designed for air movement may not necessarily provide optimal shredding capacity.